Guides to working with PDFs

Practical, specific write-ups about file size, scanning, merging, and privacy — written while building the tools on this site. No filler, no affiliate links.

01

How to get a PDF under an email attachment limit

Why a 25 MB limit only accepts an 18 MB file, how to tell where your document's weight is, and the order to try things in before you start degrading quality.

6 min read · Updated 2 August 2026
02

Lossless vs lossy PDF compression, explained properly

Two operations with almost nothing in common. Where the bytes in a PDF actually live, which technique can reach them, and why lossy compression sometimes makes a file bigger.

7 min read · Updated 2 August 2026
03

Why scanned PDFs are enormous — and how to fix it

The arithmetic of DPI and colour depth, the two scanner settings that quietly ruin files, and what to do when the scan arrives from someone else.

7 min read · Updated 2 August 2026
04

Turn phone photos of documents into one clean PDF

How to shoot, name, order, and rotate pages so the finished file looks deliberate — and when a photograph will be rejected outright.

5 min read · Updated 2 August 2026
05

What happens to a PDF you upload to an online converter

Retention policies versus technical guarantees, the documents where it genuinely matters, and a ten-second test for whether a tool really runs locally.

6 min read · Updated 2 August 2026

Start with the tools

Every guide here refers back to three free utilities that run entirely inside your browser. Nothing you open with them is uploaded, and they keep working with the network switched off.